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Press Briefing Transcript

KATHY HARBEN: Thank you, Alyssa. Welcome to this briefing on CDC’s interim travel guidance for Zika virus. We apologize for the scheduling problems today. This is a rapidly evolving investigation with new information coming in all the time. We’re doing our best to get you all of the information we can confirm. Our speakers tonight are Dr. Lyle Petersen. That’s spelled p-e-t-e-r-s-e-n. He is director of CDC’s division of vector borne diseases. We also have Dr. Cynthia Moore. That’s m-o-o-r-e. She is director of CDC’s division of birth defects and developmental disabilities. Dr. Petersen will first give remarks and then both Dr. Petersen and Dr. Moore will be available for questions. Dr. Petersen.

DR. LYLE PETERSEN: Yes. Thank you. Good evening and thank you for waiting until the evening for this announcement. So my name is Dr. Lyle Petersen. I am the director of CDC’s division of vector borne disease in Ft. Collins, Colorado. I will be providing a review of laboratory tests CDC performed on several samples received from Brazil from individuals infected with the Zika virus. I will also be sharing CDC’s interim travel guidance for the 14 countries and territories in central and South America and the Caribbean where Zika virus transmission is ongoing: Brazil, Colombia, El Salvador, French Guiana, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Suriname, Venezuela and the Commonwealth of Puerto Rico. This number will increase. I’ll close by providing an outlook of what Zika virus transmission may look like in the U.S. and moving forward.

Zika virus is spread to people through mosquito bites. About one in five people infected with Zika virus will develop the most common symptoms of Zika, including fever, rash, joint pain and conjunctivitis or red eyes. The illness is usually mild with symptoms lasting from several days to a week. Severe disease requiring hospitalization is uncommon. Outbreaks of Zika have occurred in areas of Africa, Southeast Asia, the Pacific Islands and the Americas. Because the Aedes species mosquitoes that spread the virus are found in many locations throughout the world, it is likely that outbreaks will spread to new countries. As many of you know, Brazil has been combatting a large outbreak of Zika since last year. In addition, officials there have noted a rather significant increase in cases of microcephaly, which means smaller than expected head size in infants. Many are pointing to an association between that and Zika virus infection. According to Brazilian health authorities, more than 3,500 microcephaly cases were reported in Brazil between October 2015 and January 2016. Earlier this week CDC released results from laboratory testing that represent the strongest scientific evidence to date supporting an association between Zika virus infection and microcephaly and other poor pregnancy outcomes. Although these test results provide new evidence of a link between the infection and poor pregnancy outcomes, we don’t yet know what other outcomes that might be associated with infection during pregnancy and other factors that might increase risk to the fetus. More laboratory testing and other studies are planned to learn more about the risks of Zika virus infection during pregnancy.

CDC scientists tested samples from two pregnancies that ended in miscarriage and from two infants with diagnosed microcephaly who died shortly after birth. They determined that all four cases were positive for Zika virus infection indicating that the babies had become infected during pregnancy. For the two full-time infants, tests showed that Zika virus was present in the brain. Genetic sequence analyses show that the virus in the four cases was the same as the Zika virus strain currently circulating in Brazil. All four mothers reported having experienced a fever and rash illness consistent with Zika virus disease during their pregnancies.

This new information has led CDC to issue interim travel guidance for countries where Zika virus transmission is ongoing. Until more is known, CDC recommends the following for pregnant women and women of child bearing age. Pregnant women in any trimester should consider postponing travel to the areas where Zika virus transmission is ongoing. Pregnant women who must travel to one of these areas should talk to their doctor first and strictly follow steps to avoid mosquito bites during their trip. Women of child bearing age who are thinking about becoming pregnant should consult with their health care provider before travel to these areas and follow steps to prevent mosquito bites during the trip. In addition, CDC recommends that everyone traveling to areas where Zika virus transmission is ongoing also take precautions to protect themselves from mosquito bites to reduce the risk of infection with Zika Virus and other mosquito-borne viruses such as Dengue and chikungunya. These steps included wearing mosquito repellent, using screens to keep mosquitoes outside, wearing long pants and long-sleeved shirts when possible, and emptying standing water inside and outside the home. Because specific areas where Zika virus transmission is ongoing are difficult to determine and likely to change over time, CDC will update this travel guidance as more information becomes available. Check the CDC travel website frequently for the most up to date recommendations.

Let me close by providing an outlook of what Zika virus transmission might look like in the U.S. moving forward. CDC continues to work with states to monitor for mosquito-borne diseases, including Zika. The first travel-associated Zika virus disease case among U.S. travelers was reported in 2007. From 2007 to 2014, a total of 14 returning U.S. travelers had positive Zika virus testing performed at CDC. In 2015 and 2016 at least eight U.S. travelers have had positive Zika virus testing performed at CDC. However, CDC is still receiving samples for Zika virus testing from returning U.S. travelers who became ill in 2015 or 2016. We’re not able to predict how much Zika virus will spread in the United States. Many areas of the United States have mosquitoes that can become infected with and transmit Zika virus. However, recent chikungunya and dengue outbreaks in the United States suggest that Zika outbreaks in the U.S. mainland may be relatively small and focal. In the U.S., other mosquito- spread infections like malaria and dengue used to be widespread. Better housing construction, regular use of air conditioning, use of window screens and door screens and state and local mosquito control efforts helped to eliminate these ongoing outbreaks from the mainland.

Because of this uncertainty, however, it is important that we maintain and improve our ability to identify and test for Zika and other mosquito-borne diseases. Finally, I’d like to reiterate the importance of taking precautions to avoid mosquito bites if you are traveling to an area where Zika virus transmission is ongoing. You can find information about the areas as well as more information about Zika on the CDC Zika website. Thank you and we’ll be happy to answer your questions.

KATHY HARBEN: Thank you, Dr. Petersen. Operator, we’re now ready to open up the line for questions.

OPERATOR: Thank you. We’ll now begin the question and session. Please press star one on your phone, unmute and say your name clearly. To withdraw your question press star 2. To ask a question, press star 1. Record your name. It will take a moment for questions to come through. Please stand by. Our first question comes from Richard Besser with ABC News. Your line is open.

RICHARD BESSER: Hi. Thanks so much for taking the question. My question has to do with areas of ongoing transmission. You mentioned the 14 countries. Do the recommendations apply to the entire country or just regions within those countries where there’s been transmission? Secondly, what about Americans who are residents of Puerto Rico, what do you recommend for them?

DR. LYLE PETERSEN: Right. What we’re recommending right now, given the uncertainty of exactly where Zika virus infection is ongoing in any given country, at the present time, we’re– the recommendations would follow, at least in most countries, for most of the country unless there’s specific evidence that Zika virus may not be occurring in certain areas. Again, this is an evolving situation and we expect this guidance to change in the near future. As far as residents of Puerto Rico, which would include U.S. Virgin Islands where dengue is endemic and Zika virus is likely to become epidemic in the future, what we would recommend is the usual recommendations we would take for Dengue virus infections. In other words, trying to get rid of mosquitoes around the house by emptying or getting rid of mosquito breeding sites and wearing a mosquito repellent in particular. But in particular, for pregnant women, we would expect or hope that these recommendations would be strictly followed.

OPERATOR: Next question comes from Robert Lowes with Medscape Medical News. Your line is open.

ROBERT LOWE: Thanks for taking my call. For pregnant women who are bitten by the mosquito and contract the virus, what’s the risk in terms of having a baby with this microcephaly? Can you quantify the risk in terms of like 20% risk, 100% risk?

DR. LYLE PETERSEN: We cannot quantify the risk at this time. If– we have investigations planned in Brazil in conjunction with the Brazilian health authorities to help answer these kinds of questions.

OPERATOR: Our next question comes from Marcelo Ninio with Brazilian media. Your line is open.

MARCELO NINIO: Thank you very much. My question is regarding the cases that were examined. I wanted to ask if all the cases were from Brazil? And the second question is do the number of cases in Brazil, would you say that Brazil is particularly risky for pregnant women to travel among all these 14 countries? Thank you.

DR. LYLE PETERSEN: Yeah. I think first of all, all the cases we’ve– these four cases that I mentioned were all from Brazil. As far as Brazil being particularly risky, I think this is really at this point becoming a very regional problem. I certainly wouldn’t want to focus on Brazil but pay attention to all of the countries in the region where we know virus transmission is ongoing. So it’s really impossible to say at this point in time whether Brazil is or more or less risky as opposed to other countries in the region. I think that’s why it’s really important for people traveling to the region to take these recommendations quite seriously.

OPERATOR: Our next question comes from Mike Stobbe with the Associated Press. Your line is open.

MIKE STOBBE: Hi. Thank you for taking my question. A couple things actually. First I wanted to clarify, Dr. Petersen, did you say that there were 14 cases between 2007 and 2014 and then at least 8 from ’15 to ’16? I thought the number was 12. I wanted to make sure. Also, could you say why do you think we haven’t seen this problem or have we seen this problem in other countries in earlier years in women who were infected with Zika virus?

DR. LYLE PETERSEN: Yeah. I think as far as the why haven’t we seen this problem before, the major outbreaks that occurred so far, the outbreaks that have occurred so far have been mainly in islands in the Pacific. Many of these islands have quite small populations. For example, the first outbreak that occurred was in 2007 on the island of Yap in Micronesia which has a population of 5,000. So uncommon kinds of outcomes may not have been noticed simply because there weren’t that many of them. What was noted, however, in French Polynesia where an outbreak occurred which involved more than 30,000 persons retrospectively after the Brazilian data became available– they went back and looked and saw an increase in microcephaly cases in their area. None of these have been confirmed to my knowledge, but there was an increase in microcephaly. That provides some evidence that this may be occurring in other areas as well.

OPERATOR: Our next question comes from Eben Brown with Fox News. Your line is open.

EBEN BROWN: Thank you very much for doing this. I want to commend CDC for throwing this together. I know that normally you guys are very organized. This looked like you guys sort of rushed to put this together for us in the media. Is there a degree of urgency among your colleagues and yourself regarding this? You kind– earlier today you gave us pretty short notice and then very short notice for this one. Why not wait for Monday for a press call? I’m curious about that. Second question, can you talk about what microcephaly is. You mentioned reduced head size in infant. How small are we talking and what’s the prognosis for an infant with that?

DR. LYLE PETERSEN: Right. I will answer your first question. I’m going to turn it over to Dr. Cynthia Moore for your second question. The first question, I believe, was well why not wait until Monday? The reason is we believe this is a fairly serious problem. The infection is or the virus is spreading fairly rapidly throughout the Americas. We know in populations that it does affect, a large percentage of the population may be become infected. And because of this growing risk of or growing evidence that there’s a link between Zika virus and microcephaly, which is a very severe and devastating outcome, it was important to warn people as soon as possible. As far as your second question, I will turn it over to Dr. Cynthia Moore.

DR. CYNTHIA MOORE: Thank you. When a baby is born, one of the first things that’s done is measurements. We’re all familiar with birth weight and birth length. But you may not know that a newborn baby’s head size is also measured. Microcephaly is a condition where the baby has a smaller-than-expected head when compared to other babies of the same age and sex. Unfortunately, this condition often means that the baby’s brain is also smaller and might not have developed properly. When microcephaly is severe, babies can have other symptoms such as seizures, vision problems and developmental disabilities. These symptoms can have varying degrees of severity– in some cases can be life-threatening and last for the child’s lifetime. It’s somewhat difficult to predict consequences in microcephaly at the time of a baby’s birth. Close follow-up is needed for regular checkups to monitor and evaluate these affected babies. We have more information about microcephaly on our website and invite you to look at that material. Thank you.

OPERATOR: Our next question from Donald McNeil with the New York Times. Your line is open.

DONALD MCNEIL: Can you explain exactly what the delay was all day? Is there some pressure on you to have issued this or to not issue this? Where did that pressure come from?

KATHY HARBEN: Don, this is Kathy Harben in CDC’s office of the associate director for communication. As we said earlier, we were pulling together quite a bit of information and trying to get it all ready to go at the same time. We have a media statement. We’ve also posted our travel notices now. As we said earlier, we are getting samples frequently so there was additional information that we were trying to decide if we, you know, this is something we needed to share as well. So we have pulled together what we have. You now have the travel notices. As Dr. Petersen said, we are expecting that we’re going to get more reports from more countries. And we did not want to wait until next week to share the information that we have now.

OPERATOR: Our next question comes from Susan Wagner with NBC news. Your line is open.

SUSAN WAGNER: I have two questions. The travel advisory is applying to women in all trimesters. Is there a trimester where women are more vulnerable to Zika virus? That’s my first question. Secondly, I’d like to know about mosquito spraying in the U.S. Are you going to be recommending more mosquito spraying in vulnerable areas in the U.S.?

DR. LYLE PETERSON: Yes. First, we do not know exactly what is the biggest period of risk during a woman’s pregnancy. That’s one of the things we want to find out. And maybe after I’m done, perhaps Dr. Moore can provide a little bit more insight about that. But as far as the mosquito spraying goes, many areas of the United States have very good mosquito control programs. Other areas do not. So we’re not going to necessarily recommend more mosquito spraying than what’s going on. The important thing is that we’re going to be ramping up surveillance for this across the United States, and in the event that cases start to occur, certainly we’ll hit those areas very hard. There’s just no way to spray the entire area of the United States prophylactically to try and prevent this from happening. But, when cases do occur, we’ll definitely work with states and local health departments and local mosquito control districts to jump on this and try and control it as best we can. Dr. Moore?

DR. CYNTHIA MOORE: Sure. So what we’re seeing in the babies is a destruction of brain tissue that was already– brain that was already forming. So that can happen in the first trimester, it can also happen in the second trimester. I believe that the information we have now from moms in Brazil is that most of the exposure was in the first trimester, most of the Zika virus infection was in the first trimester. But we do have some evidence that it also– the risk can continue into the second trimester.

OPERATOR: Our next question comes from Kerry Sheridan with AFP. Your line is open.

KERRY SHERIDAN: thanks for taking my question. When you talk about there are more than 3500 cases in Brazil of microcephaly in this one-year period, less than a year, can you describe how different that is from a normal period?

DR LYLE PETERSON: Dr. Moore, maybe you want to take that question.

DR.CYNTHIA MOORE: Sure. I think– unfortunately, microcephaly, which itself is a condition that is not a diagnosis. It’s very difficult to get exact numbers in populations even in the United States. We do see this as an increase. It’s very hard to say how much of an increase it is. We’re also seeing babies who have severe microcephaly, much more than we would expect but we’re hoping another area of our research or inquiry is trying to figure out exactly how much the risk for women is increased and be able to describe a little better in the population.

OPERATOR: Our next question comes from Betsy McKay with the Wall Street Journal ,your line is open.

BETSY MCKAY: Hi. Thanks. I have a question for Dr. Moore, which is I’m wondering about other associations or causes of microcephaly. Have you ever seen anything like this? In other words, a link between any other virus and microcephaly? And otherwise, what are the main causes associated with it?

DR. CYNTHIA MOORE: Well, there are many causes of microcephaly. Some are genetic causes. Some are other environmental causes, such as alcohol exposure during pregnancy. And there are other infectious causes of microcephaly. Several viruses can give you pretty much the same picture we’re seeing now with the babies that have been exposed to Zika virus. So just saying microcephaly or severe microcephaly doesn’t always point you to the cause of the problem.

OPERATOR: As a reminder, if you’d like to ask a question, please press star one and record your name. Our next question is from Dan Childs with ABC news. Your line is open.

DAN CHILDS: Thank you very much for taking my question. Knowing what we know about Zika right now, do we have any sense as to what it would take for the travel warning to go away and how long into the future might this be specifically, considering that we’re going to be looking at Olympic games in Rio in a matter of months? When might the situation be better?

DR.LYLE PETERSON: Yeah. I don’t think we can speculate on this. This is a new situation. It’s a dynamic situation. I think we’re just going to have to wait to see how this all plays out. These viruses certainly can spread in populations for some time. But, again, this is new. This is a dynamic and changing situation. I think it’s really impossible for us to speculate what may happen in three or four or even next month for that matter.

OPERATOR: Our next question comes from Mike Stobbe. Your line is open.

MIKE STOBBE: Hi. Thank you for taking me again. I just wanted to go back to the original question about the numbers and make sure it was 8 and not 12. Also, could you say what entities had input on the CDC guidance? Was there discussions with the countries that would be affected? Olympic officials, people in other federal agencies. Who had input and did any of that input influence the form that this alert came?

DR.LYLE PETERSON: Yeah. Could you repeat– sorry. Could you repeat your question? I was trying to verify the numbers here.

MIKE STOBBE: Sure. I was wondering who CDC talked to in preparation of this alert. Were the countries that were named in this alert, was it discussed with them? Did you talk to Olympic officials? Were there people in other federal agencies? What input did they have and did any of that input change the final product decision to make an alert, not a warning or anything else?

DR. LYLE PETERSON: Yeah. If Dr. Marty Cetron from our division of global migration and quarantine is on the line, he could best answer your question.

DR. MARTIN CETRON: Sure. Thanks very much. You know, as is common with all issuance of travel advisories, whether it’s our routine precautions or special precautions at level 2, which this is, or advice not to travel, we do due diligence by having consultations with impacted countries, public health authorities. We don’t like to blind side partners. We like to engage and give advance notice. Given the large number of countries in the region, the consultations are very important and very key, including our partners with the Pan American Health organization and W.H.O. It’s not so much that it changes the recommendation or the nature or the importance of the message. But I think it’s a really good practice not to surprise or put people hearing about it for the first time in the media. This is routine practice that we do with all of our travel advice. It is part of the reason that completing those consultations in a timely way and getting that back and forth is part of the reason that this process goes on long. Not so much that it fundamentally in any way changes the recommendations.

DR. LYLE PETERSON: We’ll get back to you on the number. I just want to make sure that we have it correct for you.

OPERATOR: Again, as a reminder, if you’d like to ask a question, please press star one and record your name. Stand by for any incoming questions. Our next question comes from Maggie Fox with NBC News. Your line is open.

MAGGIE FOX: Thanks. I apologize if this question has been asked. I got on the call a little bit late. Have you guys done anything to look at the denominator on the number of cases of microcephaly? I know this is hard and it’s really hard to test for Zika. But can you talk about how difficult it is to know how many cases of Zika might be directly associated with microcephaly and how you go about determining if there’s a direct cause-and-effect relationship there and whether there’s a true increase in the number of microcephaly cases in Brazil? Thanks.

DR. LYLE PETERSEN: Right. The only way to figure out exactly what the denominator is, is to do a serological survey which would involve testing hundreds or even thousands of people to look for previous exposure to the virus. And that just hasn’t been done yet. It’s a very difficult study to do, particularly in areas where dengue is endemic because the antibody tests for Zika cross-react with dengue. The types of things that we’re doing right now to answer these kinds of questions or questions similar are several– are a couple major studies are planned. One is the Brazilians are doing a study that, where they’re taking pregnant women and following them forward to look at pregnancy outcomes. We are doing a study with the Brazilians coming up in next month to what’s called a case control study where we will look at a sample of women who have been infected and have babies or excuse me have babies with microcephaly and a sample of babies without– women who had babies without microcephaly– and look for antecedent risk factors. There’s several studies either planned or ongoing to help answer questions like this.

DR. CYNTHIA MOORE: I’d like to add a little bit to that. This is Dr. Moore again. The question that I answered earlier about how common this was or do we know if there is an increase, I mentioned that it’s a very difficult condition to count in a population. In the United States, our estimate of the number of babies, born with microcephaly is between 2 and 12 per 10,000. In the Brazil babies that have been reported so far, we know that they have cast a broad net. They won’t miss any babies. But even if only, say, half of those babies had microcephaly, it would be quite a large increase.

KATHY HARBEN: Okay. Operator, can you check to see if there are any last questions?

OPERATOR: There are no questions in the queue at this time. But if you would like to ask a question, please press star 1 and record your name. Questions coming in. One moment.

DR. LYLE PETERSEN: This is Dr. Petersen. The correct number was 12. Not 14.

OPERATOR: And our next question comes from Colleen de Bellefonds with Everyday Health. Your line is open.

COLLEEN DE BELLEFONDS: Hi. I was just wondering, so when you have traveled to these areas before and maybe were unknowingly affected pre conception. Is there any concern with that or is it too early to say?

DR. CYNTHIA MOORE: This is Dr. Moore. What time period are you asking about?

COLLEEN DE BELLEFONDS: So let’s say they traveled to Brazil within the outbreak period pre-conception. They were infected. Is there a concern that if they became pregnant after that there could be some effects from that?

DR. CYNTHIA MOORE: So perhaps Dr. Petersen could answer that. My understanding is the period of concern would be about two weeks after the travel. But please correct me if I’m wrong.

DR. LYLE PETERSEN: So your question, excuse me, we were trying to reconcile something here. But could you please repeat your question?

COLLEEN DE BELLEFONDS: So let’s say someone traveled to Brazil before they knew they were pregnant. Is there any possibility at any period after that point that it could be a concern, microcephaly could be a concern?

DR. LYLE PETERSEN: Again, we don’t know exactly at what period is the major period of concern. But what I can tell you is that the virus will generally stay at least in the blood of a person who has been infected for less than a week. Now, whether– so the period that’s of concern would be rather short. Within a week or two when the person actively has virus in their blood.

COLLEEN DE BELLEFONDS: Great. Thank you.

DR. LYLE PETERSEN: To clarify the numbers issue again. From 2007 to 2014, we identified 14 individuals with Zika virus infection among travelers. From 2015 to 2016 we identified 12 so far.

KATHY HARBEN: Thank you, Dr. Petersen. And thank you everyone for joining us tonight. We’ll continue to post and share information with you as we have it. We will post a transcript on our CDC newsroom website. It probably will be sometime tomorrow. Thank you again.

OPERATOR: That concludes today’s conference. Thank you for participating. You may disconnect at this time. Speakers please stand by for post conference.